The age at which feedings should be initiated for extremely low birthweight infants is unknown. Early feedings may prevent malnutrition-related deaths. Late feedings may prevent deaths due to necrotizing enterocolitis. Our primary objective is to determine whether the routine initiation of feedings at 3 or 10 days influences the mortality of infants plus-minus 1000g birthweight given a moderate intake of parenteral fat and amino acids. Secondary objectives include the identification of differences in the incidence of necrotizing enterocolitis, duration of mechanical ventilation and hospitalization, and incidence of developmental and growth retardation at one year. The ages selected to start feeding were based in part on a recent large survey of neonatal units. To the extent feasible, the rate of feeding increase, caloric concentration of milk, total fluid intake, and indications for stopping or reducing feedings have been standardized in regimens likely to be acceptable to participating institutions. Parenteral nutrients will be provided judiciously in amounts to minimize toxicity and tissue catabolism but not to achieve active growth. A group sequential design will be used to allow the study to be terminated early if large differences in mortality are observed without violating the validity of the statistical analyses.